Health officials confirm 3 measles cases in Burlington, Ont.

In this photo Thursday, April 25, 2013 Lucy Butler,15, getting ready to have her measles jab at All Saints School in Ingleby Barwick, Teesside, England, as a national vaccination catch-up campaign has been launched to curb a rise in measles cases in England. (AP Photo/Owen Humphreys, PA)

The Halton Region Health Department is reporting three cases of measles have been confirmed in Burlington.

Health officials say all three cases involved children from the same family. Public health officials are not sure how the children were infected but say they suspect a family member may have picked up the virus while travelling outside the province.

Measles no longer circulates in Canada, but Canadians who are not vaccinated or immune through previous infection can pick it up while travelling in places where the virus is still common.

Halton health officials are also warning anyone who visited the any of the following locations on June 8 may have been exposed to measles:

The Collector’s Vault, near New Street and Guelph Line, at 10 a.m. until 1 p.m.

SportChek in Burlington Mall, Guelph Line and Fairview Street, between 1 p.m. until 4 p.m.

Al’s Source for Sports, 3485 Fairview Street, at 1 p.m. until 4 p.m.

The health department says it has already followed up individually with people who might have been exposed at a health clinic or an organized event.

The measles virus can travel in the air for several metres through fine saliva droplets and one doesn't need to come into physical contact with an infected person in order to contract it; they just need to breathe the same air they've breathed.

It takes, on average, about 10 days after exposure to the virus for symptoms to begin. Measles starts with a cough, runny nose, red, watery eyes, and fever. Typically, after the fourth day, a rash appears on the face that moves down the body.

Dr. Monir Taha, Halton region’s associate medical officer of health, tells CTVNews.ca measles patients tend to be most infectious four days before the rash begins until four days afterwards.

Infants under one year of age, pregnant women, and persons with weakened immune systems can get very ill with measles.

Complications can include pneumonia, as well as a potentially fatal inflammation of the brain called encephalitis. Dr. Taha says one in 500 patients suffer permanent brain damage from measles, while one in 1,000 die.

There is no approved treatment for measles; doctors can only manage the symptoms.

Dr. Bob Nosal, Halton Region’s medical officer of health, reminds residents that measles is preventable through immunization with two doses of vaccine.

The first dosage is typically given at a child’s first birthday, with the second does between the ages of 4 and 6.

People born before 1970 in Canada are considered immune to measles, because the disease was circulating so widely then. Canada began recommending in 1996 that everyone get two doses of vaccine and started a catch-up program to ensure that everyone born after 1979 received two doses.

It's not clear if the children had received any vaccinations, but Dr. Nosal notes that the chances of catching measles after having one vaccination is less than 10 per cent, while the risk falls to less than one per cent after two doses.

Two summers ago, there was a large measles outbreak in Drummondville, Que. A total of 776 people became ill and one out every nine required hospitalization. It was the worst outbreak in North America in 20 years.

The Quebec outbreak was likely started by someone who picked up the disease while travelling in France, which has had a number of outbreaks in recent years that have spread throughout Europe and the United Kingdom.